Bullet pen



FIG. 1 is a first side elevation view of a bullet pen showing my new design;

FIG. 2 is a second side elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a third side elevation view thereof; and,

FIG. 6 is a fourth side elevation view thereof.

The broken lines illustrate portions of a bullet pen that form no part of the claimed design. 

CLAIM The ornamental design for a bullet pen, as shown and described. 